The present invention refers to a method for defining a base line for a sparkline comprising or consisting of vertical or horizontal bars wherein the bars represent positive and negative values of a set of values, wherein the bars representing negative values extend to one side of the base line and the bars representing positive values extend to the other side of the base line and wherein the diagram is located in a space having a first and a second border.
Sparklines are word-sized graphics which may be included into texts or tables and which depict high amounts of data in small spaces. For example, sparklines comprising upward and downward bars indicate current and historical business figures, like revenues or sales, stock quotes or wins and losses for example in soccer, tennis or baseball matches.
The length/height of the bars of the sparkline corresponds to the absolute values of a set of values on which the sparkline is based.
If the set of values on the basis of which a sparkline is to be created comprises positive and negative values of a predetermined time period the bars extend from the base line of a sparkline in two directions, in case of horizontal sparklines in the upward and downward direction. Similarly in case of vertical sparklines the bars extend from the base line to the right and left direction.
The available space for representing a sparkline is limited and may correspond to the height of a box of a table or to the line height of a line of a textual document. In any case the problem arises where to locate the base line from which the bars representing the sparkline extend.